Constraints on τNLfrom Planck temperature and polarization

Abstract

AbstractWe update constraints on the amplitude of the primordial trispectrum, using the finalPlanckmission temperature and polarization data. In the squeezed limit, a cosmological local trispectrum would be observed as a spatial modulation of small-scale power on the CMB sky. We reconstruct this signal as a source of statistical anisotropy via quadratic estimator techniques. We systematically demonstrate how the estimated power spectrum of a reconstructed modulation field can be translated into a constraint onτNLvia likelihood methods, demonstrating the procedures effectiveness by inferring knownτNLsignal(s) from simulations. Our baseline results constrainτNL< 1700 at the 95% confidence level, providing the most stringent constraints to date.